U.S. patent application number 10/253807 was filed with the patent office on 2003-03-27 for urine detection system and method.
This patent application is currently assigned to Sysmore, Inc.. Invention is credited to Shapira, Shmuel, Tsur, Ron A..
Application Number | 20030060789 10/253807 |
Document ID | / |
Family ID | 27569475 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030060789 |
Kind Code |
A1 |
Shapira, Shmuel ; et
al. |
March 27, 2003 |
Urine detection system and method
Abstract
A urine detection system and method. According to one aspect of
the invention, the method includes generating a magnetic field
within an effective distance of a potentially wetted area, and
conducting a plurality of measurements to construct a magnetic
energy distribution function corresponding to the potentially
wetted area. The method further includes comparing at least one
parameter of the magnetic energy distribution function to a set of
stored parameters corresponding to known wetness conditions to
identify a wetness condition of the potentially wetted area.
Inventors: |
Shapira, Shmuel; (Sherwood,
OR) ; Tsur, Ron A.; (Banks, OR) |
Correspondence
Address: |
Kolisch Hartwell, P.C.
200 Pacific Building
520 S.W. Yamhill Street
Portland
OR
97204
US
|
Assignee: |
Sysmore, Inc.
|
Family ID: |
27569475 |
Appl. No.: |
10/253807 |
Filed: |
September 23, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60324278 |
Sep 25, 2001 |
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60344795 |
Jan 7, 2002 |
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60348381 |
Jan 16, 2002 |
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60354530 |
Feb 8, 2002 |
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60357624 |
Feb 20, 2002 |
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60373637 |
Apr 19, 2002 |
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Current U.S.
Class: |
604/361 ;
604/362 |
Current CPC
Class: |
A61F 2013/8491 20130101;
A61F 2013/8488 20130101; A61F 13/42 20130101; A61F 13/84
20130101 |
Class at
Publication: |
604/361 ;
604/362 |
International
Class: |
A61F 013/15 |
Claims
What is claimed is:
1. A method of detecting urine, comprising: generating a magnetic
field within an effective distance of a potentially wetted area;
conducting a plurality of measurements to construct a magnetic
energy distribution function corresponding to the potentially
wetted area; and comparing at least one parameter of the magnetic
energy distribution function to a set of stored parameters
corresponding to known wetness conditions to identify a wetness
condition of the potentially wetted area.
2. The method of claim 1, wherein generating a magnetic field
includes driving a signal through an exciter coil.
3. The method of claim 1, wherein the plurality of measurements are
correlated in time to different frequencies of the magnetic
field.
4. The method of claim 1, wherein the plurality of measurements are
correlated in time to the build up and collapse of the magnetic
field.
5. A urine detection system, comprising: an inducer configured to
generate a magnetic field within an effective distance of a
potentially wetted area; an energy-converting module configured to
conditionally engage in mutual induction with the inducer; and an
analyzing module configured to construct a magnetic energy
distribution function that models an energy distribution pattern
between the inducer and the energy-converting module, wherein the
analyzing module is further configured to apply the magnetic energy
distribution function to a set of stored parameters corresponding
to known wetness conditions to identify a wetness condition of the
potentially wetted area.
6. The urine detection system of claim 5, wherein the
energy-converting module is one of a plurality of energy-converting
modules, each energy-converting module configured to conditionally
engage in mutual induction with the inducer.
7. The urine detection system of claim 6, wherein the plurality of
energy-converting modules constitute a urine detection network for
detecting relative amounts of urine at a plurality of regions of a
urine collection article.
8. The urine detection system of claim 6, wherein the plurality of
energy-converting modules are configured as one resonator.
9. The urine detection system of claim 5, wherein the inducer and
the energy-converting module are movable relative to one
another.
10. The urine detection system of claim 9, wherein the inducer and
the energy-converting module are tuned to conditionally resonate
with one another.
11. The urine detection system of claim 10, wherein the
energy-converting module is insulated from urine.
12. The urine detection system of claim 10, wherein the
energy-converting module is configured to lose its ability to
enterer a state of resonance when short-circuited by urine.
13. The urine detection system of claim 10, wherein the
energy-converting module is configured for selective attachment to
a urine collection article.
14. The urine detection system of claim 10, wherein the
energy-converting module is incorporated into a urine collection
article.
15. The urine detection system of claim 5, wherein the analyzing
module is configured to measure an induced signal at the
energy-converting module.
16. The urine detection system of claim 15, further comprising a
second energy-converting module, wherein the analyzing module is
configured to monitor a relative difference in the induced signals
at each energy-converting module.
17. The urine detection system of claim 16, wherein the
energy-converting modules are spaced in fixed positions on opposite
sides of the inducer.
18. The urine detection system of claim 5, wherein the analyzing
module compares parameters of the energy distribution function with
the stored parameters.
19. The urine detection system of claim 18, wherein the analyzing
module includes a processor for executing stored instructions to
compare parameters of the energy distribution function with the
stored parameters.
20. The urine detection system of claim 5, wherein the analyzing
module implements a real-time adaptive monitoring strategy to
construct the energy distribution function.
21. The urine detection system of claim 5, wherein the analyzing
module includes a memory for storing the parameters corresponding
to the known wetness conditions.
22. The urine detection system of claim 5, wherein the
energy-converting module includes a coil for conducting an electric
current induced by the magnetic field.
23. The urine detection system of claim 5, wherein the
energy-converting module includes a mechanical converter for
converting energy from the magnetic field to mechanical energy.
24. The urine detection system of claim 5, wherein the analyzing
module compares a magnetic energy distribution function constructed
during an ascending frequency sweep of the magnetic field with a
magnetic energy distribution function constructed during a
descending frequency sweep of the magnetic field to identify a
hysteretic effect.
25. The urine detection system of claim 5, wherein two or more
energy-converting modules are configured to respond differently to
the same magnetic field.
26. The urine detection system of claim 5, wherein the analyzing
module is configured to extract data embedded in transferred
energy.
27. A urine detection system, comprising: an inducer configured to
generate a magnetic field; a sampling coil configured to convert
magnetic energy of the magnetic field into an induced signal; an
analyzing module configured to monitor induced signal behavior at
the sampling coil and recognize induced signal behavior that
indicates a volume of urine is within an effective distance from
the sampling coil.
28. The urine detection system of claim 27, wherein the sampling
coil is fixed adjacent the inducer.
29. The urine detection system of claim 27, further comprising a
reference coil configured to convert magnetic energy of the
magnetic field into an induced signal, wherein the analyzing module
is configured to monitor a relative difference in induced signal
behavior at the sampling coil compared to the reference coil, and
recognize a relative difference that indicates a volume of urine is
within an effective distance from the sampling coil.
30. The urine detection system of claim 29, wherein the sampling
coil and the reference coil are respectively fixed adjacent
opposite sides of the inducer.
31. The urine detection system of claim 27, wherein the analyzing
module implements a real-time adaptive monitoring strategy.
32. An excretion retention article, comprising: an absorbent region
for retaining an excretion; and an energy-converting module
configured to conditionally collaborate with an inducer, wherein an
energy distribution between the energy-converting module and the
inducer is influenced according to an amount of excretion retained
by the absorbent region.
33. The excretion retention article of claim 32, wherein the
excretion is urine.
34. The excretion retention article of claim 32, wherein the
energy-converting module is insulated from the excretion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
from the following co-pending provisional patent applications,
which are incorporated herein by this reference, in their entirety,
and for all purposes: Wetness Detector and Messaging System, Serial
No. 60/324,278, filed Sep. 25, 2001; Monitoring and Messaging
System, Serial No. 60/344,795, filed Jan. 07, 2002; Monitoring and
Messaging System, Serial No. 60/348,381, filed Jan. 16, 2002;
Monitoring and Messaging System, Serial No. 60/354,530, filed Feb.
8, 2002; A System and a Method for Monitoring Fluid in Absorbent
Articles, Serial No. 60/357,624, filed Feb. 20, 2002; and
Contact-less Monitoring and Messaging System, Serial No.
60/373,637, filed Apr. 19, 2002.
BACKGROUND OF THE INVENTION
[0002] In the past, detecting the presence of urine, for instance
in a diaper or bedding, has been accomplished by physically
touching the potentially wetted area. For convenience, speed,
sanitation, and similar reasons, this method is less than ideal,
particularly in a managed care environment. In such environments,
urine detection is an ongoing process. Several patients may need to
be repeatedly tested, which can be a time consuming, physically
demanding, undesirable task. Often times, patients are in beds,
covered with blankets, and testing for urine in such circumstances
is difficult using conventional methods. Some detection methods
utilize visual indicators, but these methods require removal of
clothing and/or blankets, and cannot discretely be used by an adult
wearing a diaper in public.
[0003] To maximize the utility of urine collection articles, such
as diapers, such articles must be changed when they have collected
the proper amount of urine. Changing a urine collection garment too
soon can be wasteful because the maximum effectiveness of the
garment is not utilized. Changing a garment too late may cause the
wearer discomfort and/or irritation, and may also allow urine to
spread outside of the garment. Therefore, to maximize the
effectiveness of such garments, it is desirable to be able to
determine the relative amount of urine that has been collected by
such a garment so that the garment may be changed at the proper
time.
SUMMARY OF THE INVENTION
[0004] A urine detection system and method are provided. According
to one aspect of the invention, the method includes generating a
magnetic field within an effective distance of a potentially wetted
area, and conducting a plurality of measurements to construct a
magnetic energy distribution function corresponding to the
potentially wetted area. The method further includes comparing at
least one parameter of the magnetic energy distribution function to
a set of stored parameters corresponding to known wetness
conditions to identify a wetness condition of the potentially
wetted area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a schematic view of a urine detection system
according to an embodiment of the present invention.
[0006] FIG. 2 is a schematic view of an exemplary urine detection
wand collaborating with a corresponding exemplary energy-converting
module in accordance with an embodiment of the present
invention.
[0007] FIG. 3 is a schematic view of a urine collection article
configured for use with the urine detection wand of FIG. 2.
[0008] FIG. 4 is a graph of response curves generated from
measurements taken with a urine detection system in accordance with
an embodiment of the present invention.
[0009] FIG. 5 is another graph of response curves generated from
measurements taken with a urine detection system in accordance with
an embodiment of the present invention.
[0010] FIG. 6 is a schematic view of a urine detection system in
accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0011] A urine detection system in accordance with some embodiments
of the present invention is schematically illustrated at 10 of FIG.
1. As described in detail below, the urine detection system may be
used to detect urine excretions, such as in a diaper, clothing,
bedding, etc. Easy and accurate detection of urine excretions may
be particularly useful in a managed care environment, although the
present invention may be used to detect urine, or other ionized
substances, in virtually any environment for virtually any purpose.
For example, embodiments of the present invention may be used to
detect excretions of an infant or those occurring when an
individual is being trained to use a toilet and/or stop
bed-wetting, as well as when an individual suffers from urinary
incontinence. Some embodiments of the present invention permit
urine detection measurements to be performed through clothing
and/or bedding, and each measurement may be performed in a matter
of seconds without having to unnecessarily move the tested
individual. Furthermore, it is within the scope of the invention to
test not only the presence of urine, but also the amount of urine
present. As described below, the urine detection system may include
one or more dedicated devices configured to detect the presence of
urine. In some embodiments, componentry of the system may be
distributed between one or more devices that may also be configured
to provide functionality other than urine detection
functionality.
[0012] Urine detection system 10 includes a detection wand 12 and
at least one energy-converting module 14. As shown, the detection
wand may include an inducer 16 and an analyzing module 18. The
inducer may be designed to introduce a magnetic field into a test
environment, such as a diaper. In some embodiments, the inducer may
include a signal generator 22, such as a radio frequency
oscillator, operatively coupled to an exciter coil 24 so that the
signal generator may drive an electrical signal in either transient
or continuous form through the exciter coil to produce the desired
magnetic field. The signal generator may include a
voltage-controlled oscillator, phase-lock-loop based synthesizer,
direct digital synthesizer, etc. The signal generator may be
configured to selectively adjust the waveform, frequency, or duty
cycle of the driven signal to produce the desired magnetic field.
As described herein, the driven signal may be adjusted, for example
by a system controller 20.
[0013] Changing current in the inducer may vary the magnetic flux
through the energy-converting module, and thus, may induce an
electromotive, mechanical, or other force in the energy-converting
module. Therefore, the inducer and the energy-converting module may
engage in mutual inductance with one another, as well as other
participating elements, such as other energy-converting modules.
The energy distribution between the energy-converting module and
the inducer may be measurably influenced when the urine detection
system is within an effective distance from a volume of urine.
Therefore, measurement and analysis of the energy distribution may
be used to detect urine. The effective distance may vary
considerably depending on the configuration of the urine detection
system. In some embodiments, an energy-converting module may be
physically separated from the urine detection wand, and in some
embodiments, the energy-converting module may be incorporated into
the urine detection wand, as a sampling coil, for example.
[0014] The energy-converting module may utilize a conductive loop
(coil) to convert magnetic energy into electrical energy. Such a
coil may be utilized in various embodiments of the present
invention via at least two methods. Using one method, the coil may
be employed to directly measure energy distribution. In such a
configuration, herein referred to as a sampling or reference coil,
the coil may be fixed relative to the inducer, and the induced
voltage in the coil may be measured across the coil. Using the
other method, the coil may collaborate with the inducer to
facilitate detection of urine, although measurements are taken
apart from the coil itself. Such a coil, herein referred to as a
collaborating coil, may be movable relative to the inducer, and is
typically configured as a part of a resonance circuit. In either
case, such energy-converting modules may include one or more
components that collectively constitute the sampling coil or
collaborating coil. Furthermore, it should be understood that
sampling coils and collaborating coils may be variously configured
depending on the particular configuration of a particular urine
detection system.
[0015] In some embodiments, the energy-converting module includes a
collaborating coil configured as a part of an inductive/capacitive
resonating circuit, as is described in detail below with reference
to FIG. 2. With such an energy-converting module, mutual
oscillation between the inducer and the energy-converting module
may occur if the distance between the inducer and the
energy-converting module is within an operating range, and the
frequency of the generated alternating magnetic field corresponds
to the resonant frequency of the energy-converting module. The
mutual oscillation typically is characterized by a measurable
increase in the amount of energy being exchanged between the
inducer and the energy-converting module, which is reflected in the
energy distribution between the inducer and the energy-converting
module. As described below, ionized substances, such as urine, may
affect the energy distribution. It should be understood that it is
also within the scope of the invention to implement other
non-electrical resonators, such as mechanical resonators including
a magneto elastic resonator. Two or more resonators configured to
differently affect the energy distribution of the system in the
presence of a quantity of ionized substance may be utilized to
provide comparative information or to validate results.
[0016] In some embodiments, the energy-converting module may
include a sampling coil, as is described in detail below with
reference to FIG. 6. In such embodiments, the induced signal at the
sampling coil may be measured across the coil itself. Furthermore,
it is within the scope of the invention to include an optional
reference coil, from which a reference signal may be measured. The
sampling coil may be configured to respond to a particular magnetic
field in the same way as the reference coil so that discrepancies
detected between the sensing and reference coils may be attributed
to external factors. For example, a sampling coil and a reference
coil may be fixed at substantially equal distances and in similar
orientations relative the inducer. In an isolated environment, the
inducer typically will induce equal (or nearly equal) electromotive
forces in the sampling coil and the reference coil if the coils are
similarly configured. Therefore, the effects of outside influences,
such as urine, which may depend on position relative to the coils,
may be measured and analyzed. In some embodiments, the sampling
coils may not be similarly configured and/or similarly spaced
relative the inducer. However, it should be appreciated that in
such configurations, differential measurements are still
possible.
[0017] Analyzing module 18 may be configured to measure energy
distribution between the inducer and one or more energy-converting
modules. The analyzing module may include a sampling coil 26 for
taking such measurements. Exciter coil 24 of the inducer may
alternatively or additionally be used to take such measurements. It
is within the scope of the invention to utilize more than one
sampling coil in order to facilitate differential signal
measurements. The analyzing module is typically integrated into the
urine detection wand, although it is within the scope of the
invention to externally house the analyzing module, or portions
thereof. Data acquisition componentry of the analyzing module may
also be configured to receive measurements from other sources.
Analyzing module 18 typically includes an analog-to-digital
converter for converting analog signals into digital information.
The digital information may be analyzed and/or stored. In
particular, the analyzing module may store digital information
constituting a constructed energy distribution function that models
the measured energy distribution pattern. The analyzing module may
include system memory for storing a set of parameters corresponding
to known wetness conditions, as well as other conditions such as
magnetic coupling coefficients, as described below. A processor of
the analyzing module may execute instructions that evaluate the
magnetic energy distribution function, such as by comparing
parameters of the function to the set of stored parameters
corresponding to known conditions. In this manner, the measured
energy distribution pattern may be linked to a wetness condition
corresponding to a pre-determined energy distribution pattern, as
represented by the stored parameters in system memory.
[0018] The analyzing module may include a system controller 20 for
performing a variety of supervisory functions including data
acquisition and storage, decision-making, scheduling, coordination,
and execution of the other various system functions discussed
herein. For example, the controller may be configured to set the
signal driven through the inducer, analyze received data, compare
received data with data derived from known wetness conditions,
adjust the driven signal based on the analyzed data, etc. The
system controller may initiate an automatic detection mode in which
data acquisition cycles are executed according to preset time
intervals, or the system controller may defer scheduling to a
tester or a separate system. The system controller may include a
processor, such as an embedded hardware microcontroller, which may
include, or interface with, data storage devices and/or peripheral
devices, such as timers, counters, I/O ports, etc. In addition, the
wand may also include a power supply 28 and a notification
subsystem 29.
[0019] The urine detection wand may be configured in a variety of
shapes and/or sizes. In particular, the wand may be sized and
weighted for easy manual manipulation by a tester. For example, a
hand-held wand may be used to reach around a bedded patient without
having to move the patient. The relatively small size of the wand
also may permit the wand to be easily carried from one test area to
the next, for example, to test several patients located in several
different rooms. It is also within the scope of the invention to
incorporate the urine detection wand, or parts of it, into another
device, such as a personal data assistant, watch, cellular phone,
glove, belt, etc. The system may communicate with other systems
through a communication interface, such as a wired or wireless
communication interface. The required proximity of the urine
detection wand relative to the potentially wetted area may vary
depending on the particular configuration being used.
[0020] As is described with reference to the following illustrative
examples, the urine detection system may be variously configured.
In some embodiments, energy-converting modules of the urine
detection system may include a sampling coil, while others may
include a collaborating coil, such as a resonator. Some systems may
utilize both collaborating coils and sampling coils. Furthermore,
an energy-converting module of a particular urine detection system
may be spatially fixed relative to the inducer, or may be freely
movable relative to the inducer. It is also within the scope of the
invention to use a combination of fixed and movable
energy-converting modules. Similarly, exposed energy-converting
modules and energy-converting modules insulated from contact with
an ionized substance, such as urine, may be variously implemented.
Some energy-converting modules may include additional circuitry for
modifying the transferred energy to include identifiable
characteristics, such as modulation. Such a configuration may be
employed to facilitate differentiation between closely located
modules. Furthermore, some energy-converting modules may include a
data storage mechanism for storing data, such as an identifier that
may be presented to an analyzing module to facilitate
identification of a particular energy-converting module. This may
be useful, for example, if a common analyzing module is used in
conjunction with more than one energy-converting module. It should
be understood that many combinations are possible, and the
following are provided as non-limiting illustrative examples.
[0021] FIG. 2 shows a urine detection system 30 that includes a
detection wand 32 with an inducer 34 and analyzing module 36. The
wand also may include a power supply 38 and a notification
subsystem 40. As shown, an energy-converting module 42 in the form
of a collaborating coil is separated from and movable relative to
the urine detection wand. The energy-converting module includes an
inductive/capacitive resonating circuit in a planar configuration.
Such a resonator may be very small. In the illustrated embodiment,
the resonator is shown to be approximately the size of a postage
stamp (1 inch.times.1 inch.times.0.02 inch), although larger or
smaller resonators are within the scope of the invention. The
resonator may be passive, and therefore not require a dedicated
power source. The resonator's small size, and its ability to
operate without a dedicated power source, allow the resonator to be
used in a variety of different applications. For example, the
resonator may be configured as a tag or decal that may be
selectively attached to a urine collection article 44, as is
illustrated in FIG. 2. Such a configuration allows for aftermarket
modification of any urine collection article. Urine collection
articles may include absorbent garments, diapers, absorbing pads,
under garments, bed coverings, urine bags, and other types of
garments and sanitary products. As is discussed below, the
energy-converting module may be secured to the outer-surface of a
diaper, and need not come in direct contact with urine. The
resonator may also be integrated into a urine collection article
(insulated or non-insulated). In either case, the close association
with a potentially wetted area may increase detection accuracy in
some applications.
[0022] More than one energy-converting module may be included in
the urine detection system. For example, FIG. 2 shows a second
resonator 42', which has natural resonance frequency different than
the natural resonance frequency of resonator 42, is attached to
another area of urine collection article 44. Plural
energy-converting modules allow different areas of a urine
collection article to be tested, so that the relative wetness of
the various areas may be determined. This may be useful in
determining if a urine collection article is ready for changing,
for example by recognizing the differential wetness characteristics
of different regions of a garment to determine the difference from
a lightly wetted garment and a garment that should be changed.
Furthermore, two or more coils may be connected to one another and
at least one capacitor to constitute a single electrical resonator
that may enter a state of resonance when at least one of the coils
is within the magnetic field of the inducer. In this manner, plural
energy-converting modules may be networked together, so that
participation of one energy-converting module may yield information
relating to the wetness of an area associated with both itself and
another energy-converting module. In other embodiments, a single
elongated collaborating coil 45 may be used in conjunction with a
urine collection article 47, as shown in FIG. 3. Such an elongated
collaborating coil may be positioned so that as the urine
collection article becomes increasingly saturated, a greater
percentage of the collaborating coil will be within an effective
range from the urine. Therefore, the relative amount of urine
collected may be identified.
[0023] The energy-converting modules may be insulated from urine by
positioning the module outside of a protective shell of an
absorbent article and/or via a moisture shell 46. As used herein,
"insulated from moisture, excretion, and/or urine" describes an
energy-converting module with functional components physically
protected from urine. The moisture shell and/or other
non-functional components may come into contact with urine.
Similarly, the urine may affect the energy-converting module, such
as via magnetic fields. The moisture shell may be a waterproof
envelope or other suitable structure or coating for preventing
urine from contacting the circuitry of the module. The moisture
shell may be useful in preventing urine from directly interacting
with metals or other materials that may be used to construct the
energy-converting module, thereby limiting potential harm to a body
exposed to the urine. The moisture shell may also prevent urine
from shorting an electrical circuit included in an
energy-converting module.
[0024] Of course, in some embodiments, an energy-converting module
without a moisture shell may be used. Such an energy-converting
module, which may include an electrical resonator, may be
configured to lose its ability to attain mutual oscillation when in
the presence of urine, because it is short circuited, for example.
Therefore, the non-insulated energy-converting module may serve as
an indication of the presence of urine, even for small quantities
of urine. An energy-converting module insulated from moisture may
be used in combination with a non-insulated module to facilitate
quantity-related detection. Furthermore, the insulated
energy-converting module may be used to determine that a
non-insulated energy-converting module is not participating as a
result of a condition other than contact with urine.
[0025] In application, detection wand 32 may be used to collaborate
with one or more energy-converting modules, such as module 42
and/or module 42'. As described above, inducer 34 may generate an
alternating magnetic field, which may be at least partially
absorbed by the energy-converting modules. The analyzing module may
then track changes in the energy distribution between system
components. In general, the energy that is exchanged between the
inducer and an energy-converting module(s) depends on the magnetic
coupling coefficient, their relative impedance, and the frequency
of the magnetic field. An ionized substance may affect the
impedance of a system component, such as by changing parasitic
capacitance or magnetic permeability, and/or change the properties
of the magnetic field such as by absorption or distortion.
[0026] Mapping the behavior of the system during a data acquisition
cycle yields one or more response curves, and/or magnetic energy
distribution functions, representing the energy distribution
pattern, as described below with reference to FIGS. 4 and 5. A
response curve may represent time-correlated variations in signal
amplitude to different frequencies of an alternating magnetic field
as measured at different locations within the system. Similarly, a
response curve may represent variation of signal level in time,
correlated with the build up and collapse of a magnetic field
associated with an electrical pulse.
[0027] In the present implementation, the detection system is
designed so that the energy distribution reacts to an ionized
substance located at an effective distance within the shared
magnetic field, and yields a system response curve and/or magnetic
energy distribution function that is distinctly different from when
the system is inert. Therefore, analysis of the response curve
and/or magnetic energy distribution function may be used to detect
the presence of urine, which is an ionized substance. If the system
is allowed to enter into a state of sympathetic oscillation, the
response curve may exhibit a unique behavior associated with a
hysteretic effect. Identifying this hysteretic effect may provide
an additional method of distinctly characterizing system response,
which is not solely dependent on amplitude measurements, and may
potentially improve the system's signal to noise ratio.
[0028] The orientation and/or distance between the inducer and an
energy-converting module may affect the value of the magnetic
coupling coefficient (K). Therefore, accurate urine detection may
depend on properly identifying the magnetic coupling coefficient.
FIG. 4 shows eight curves corresponding to wet and dry measurements
respectively taken at distances of 6 mm, 16 mm, 29 mm, and 41 mm.
The distance between an energy-converting module and the inducer
directly affects the K value. As shown, different Ks typically
result in different response curves for respective dry and wet
conditions. A response curve associated with a specific K may also
be found in an intermediate position between a curve representing a
dry condition and a curve representing a fully wet condition. It is
also within the scope of the invention to process curves that
represent a partially wetted condition.
[0029] Parameters from a plurality of known energy distribution
patterns may be stored in system memory and used to identify a
coupling coefficient during a urine detection procedure. For
example, parameters from a magnetic energy distribution function
that models a measured energy distribution pattern may be compared
to stored parameters, which act as a reference. In this manner, the
measured energy distribution pattern may be linked to a known
energy distribution pattern, and the coupling coefficient
associated with the known energy distribution pattern may be
extrapolated to the measured energy distribution pattern. Two or
more energy-converting modules, each configured to respond
differently to the same magnetic field, such as by having a
different resonance frequency and resistance, may be employed to
provide comparative information and assist in calculating K.
[0030] Identification of the relevant K value typically greatly
improves detection accuracy and helps properly translate observed
energy levels into useful information regarding the presence or
quantity of urine in the tested region. The system may compensate
for changing K values by using mathematical modeling of expected
signal behavior for specific discrete values of K. Techniques such
as curve fitting and interpolation facilitate the numerical
approximation of a curve to be performed using only a limited
number of control parameters. Movement between the inducer and
energy-converting modules during a data acquisition cycle may be
compensated for by adaptive monitoring strategies. Differences
between the response curves of two or more consecutive measurements
may indicate the occurrence of movement. Changes in system response
that can be attributed to movement may than be calculated and
compensated for.
[0031] A data acquisition cycle may involve a frequency sweep
within a predetermined range while concurrently sampling
(measuring) a signal representing the level of energy in a chosen
region in the system. As discussed above, signal sampling may
include digital to analog conversion of measured signals, whereby
the measured signals are successively sampled at fixed intervals to
produce a series (set) of discrete measurement values that, in
turn, may be stored in system memory, either individually, as a set
of values, or as a set of parameters defining a constructed
magnetic energy distribution function. The signal-sampling rate may
be synchronized with the rate the inducer changes the frequency of
the generated magnetic field (sweep rate). This helps ensure that
each discrete measurement is closely associated with a known
frequency, or frequency sub-range. Using this cycle, an array of
numerical values representing the instantaneous energy for each
frequency (sub-range) may be acquired and selectively stored in
memory for further analysis. For example, using the array, the
acquired signal frequency-amplitude response curve may be studied
for characteristic patterns that indicate various wetness
conditions associated with different Ks. Depending on the
application, the frequency sweep method may be either ascending
(low frequency to high frequency), descending (high frequency to
low frequency), or virtually any combination of ascending and
descending sweeps. Furthermore, the frequency range for each sweep
may be strategically focused about a particular active range to
improve detection accuracy.
[0032] In addition to controlling the range of the frequency sweep,
the rate at which the frequencies are swept may also be
strategically adjusted. Similarly, the sensitivity of signal
detection may be adaptively adjusted to compensate for weak signals
or reduce noise detection. The system may be equipped with a gain
control device for adjusting the dynamic range of the amplitude of
the driven signal. When the system is activated, the gain control
settings are typically configured to a default value. The default
value may provide a balance between low gain, where small changes
in signal level may be difficult to detect, and high gain, where
noise may be introduced. The system may maintain a circular
histogram, containing the weighted averages for the most recent
signal acquisition cycles, which may be used to adaptively adjust
the setting of the gain control to an optimal position. Frequency
range, sweep pattern, sweep rate, sensitivity, and other
acquisition and analysis procedures may be strategically adapted
alone or in combination.
[0033] The data analysis process typically involves extracting
significant details from the data gathered during the most recent
acquisition cycle (or a collection of the most recent cycles),
calculating the system response curve/function, and interpreting
the response curve/function. Selective regions of the curve may be
identified as indicating significant events, such as a wetness
condition. Data may be evaluated according to stored parameters
representing pre-measured test curves that correspond to different
combinations of Ks, urine quantities, and/or other variables (known
conditions). Such evaluations may be useful in identifying the
measured response curve. For example, a response curve may be
matched to a particular test curve because the curves have
substantially similar parameters. The conditions of the known test
curve, such as relative wetness, coupling coefficient, etc., may be
used to extrapolate the conditions of the potentially wetted area,
and such conditions may be reported to a tester via the
notification subsystem, which may include a display, audio speaker,
data transmission interface or other suitable notification and/or
communication mechanism.
[0034] The analyzing module may be designed to recognize
measurements that are less than optimal due to the orientation or
position of the urine detection wand. Furthermore, the analyzing
module may be configured to alert an operator, such as via
notification subsystem 40, that the disposition of the urine
detection wand should be reorientated to achieve optimal
measurements. The notification subsystem may also be configured to
alert a tester to other conditions, such as a low battery
condition, an error condition, etc.
[0035] FIG. 5 graphically illustrates measured response curves
corresponding to ascending and descending frequency sweeps for
exemplary wet and dry conditions. The depicted response curves
represent a configuration having a collaborative coil attached to
the external side of a protective shell of an absorbent pad, and
measurements where taken across a sampling coil positioned 25 mm
away from the exciting coil. Response curves 50 and 52 respectively
represent ascending and descending frequency sweeps during a dry
condition, while response curves 54 and 56 respectively represent
ascending and descending frequency sweeps during a wet condition.
For the purpose of simplicity, only a single ascending and
descending sweep is shown for the respective wet and dry
conditions. However, in practice, several ascending and/or
descending frequency sweeps may be performed each second; and each
sweep may be dynamically adjusted based on the current monitoring
strategy. The results from each sweep may be considered
individually and/or the results of several sweeps may be considered
together, such as in a weighted average. Also, for the purpose of
simplicity, each of the illustrated response curves corresponds to
a measurement that was taken with the urine detection wand in the
same orientation and position relative to the energy-converting
module. The direction of the sweep, and the presence of urine are
the only altered variables. Of course, in practice, the detection
wand may move relative to the energy-converting module, and such
movement may be reflected in the measured response curves. However,
it is within the scope of the invention to limit potentially
negative effects of such movement via software filters and/or
adaptive monitoring strategies. For example, software may be
executed to link an array of measured signals represented by a
response curve or magnetic energy distribution function to known
response curves associated with known K values and wetness
conditions.
[0036] As is shown, the response curves span between 9.00 MHz and
10.00 MHz, the range of the frequency sweep used to measure the
response curves in the illustrated example. Of course, other
frequency ranges may be used. The four response curves generally
track each other between 9.00 MHz and 9.40 MHz. Because this
portion of the curves is not as dependent on relative wetness, it
may be useful in determining the K value when the relative wetness
is not known. Between 9.40 MHz and 10.00 MHz, it can be seen that
the response curves do not track each other. This range provides
useful information regarding the wetness condition of the measured
environment. However, it should be understood that useful
information may be extracted from other ranges, depending on the
frequency the energy-converting module is tuned or similar
factors.
[0037] Comparing dry curves 50 and 52 to wet curves 54 and 56, it
may be appreciated that while the wet curves generally slowly
increase in amplitude from 9.40 MHz to 9.50 MHz and then gradually
decrease while moving to 10.00 MHz, the dry curves demonstrate an
exaggerated increase in amplitude above 9.40 MHz and then an
exaggerated decrease in amplitude before gradually moving towards
the wet curves at 10.00 MHz. The dry curves respectively have
maximum amplitude inflection points 58 and 60 and minimum amplitude
inflection points 62 and 64 that help differentiate the wet curves
from the dry curves. The wet curves also have maximum and minimum
inflection points, however, the following discussion will focus on
the dry curves for the purpose of simplicity.
[0038] The variation in signal amplitude, as shown between the
maximum and minimum inflection points and nearby frequency ranges,
can be used to determine the response curve associated with the
energy transfer pattern exhibited by the system. Characterization
of the curve may involve any of the following parameters: rate of
change, span between inflection points, maximum and minimum, trend,
repetition, and other parameters derived from numerical and
statistical analysis methods such as Fourier Analysis. It should be
understood, however, that other parameters may also be used.
Furthermore, such parameters may be used to individually
characterize each measured curve, and the parameters may be stored
and/or used to compare measured curves to known curves. The
parameters may define a magnetic energy distribution function that
may be used in system testing.
[0039] The analyzing module may analyze measured curves in order to
identify similarities and/or differences with respect to known
curves associated with known Ks and wetness conditions. Such
analysis may include comparisons between significant features of
the respective curves, as may be characterized by one or more
relevant parameters. In addition to curve parameters, the
conditions present during the measuring of the known curves may be
stored in memory, and used to determine the conditions present
during a urine detection measurement. An example comparison may
include comparing at least one parameter derived from measured
behavior with a corresponding known parameter from a known response
curve and determining if the derived parameter is within a
predetermined range relative to the corresponding parameter from
the known response curve. Such a comparison may be repeated for a
series of parameters. If the comparisons link the measured behavior
to a known behavior, according to pre-determined tolerance
criteria, the conditions associated with the known behavior
(relative wetness, wand disposition, etc.) may be extrapolated to
the measured environment. In this way, curve comparisons may be
used to identify the state of the measured system's behavior by
relating known information about pre-measured behavior, such as
wand disposition and relative wetness, to the measured behavior.
The results of such comparisons may be used to convey information
regarding the content of a urine collection article, such as a
diaper, via a notification subsystem. An energy-converting module
may modify the transferred energy to include identifiable
characteristics. The analyzing module may extract such data,
embedded in the response curve, and use it in the analysis process
or forward the information for external analysis.
[0040] Identification of a hysteretic effect may provide useful
information regarding the state of the system. For example, maximum
inflection point 58 for the ascending dry curve occurs at a lower
frequency than maximum inflection point 60 for the descending dry
curve, although the respective sweeps were generated in a common
environment. Similarly, minimum inflection point 62 for the
ascending dry curve occurs at a lower frequency than minimum
inflection point 64 for the descending dry curve. As shown, the
frequency-amplitude response curve exhibits a unique non-linear
behavior associated with a hysteretic effect. Characterizing this
hysteretic effect provides a method of distinctly characterizing
system response, which is not solely dependent on amplitude
measurements while improving the measurement system's signal to
noise ratio.
[0041] As discussed herein, the system may adapt a monitoring
strategy to better interpret curve behavior. For example, with
respect to the measurements shown in FIG. 5, after recognizing that
the curves approximately track one another between 9.00 MHz and
9.40 MHz, subsequent sweeps may be focused between 9.40 MHz and
10.0 MHz, which may allow for improved resolution and potentially
increased accuracy. Similarly, gain may be increased or decreased
to adjust the sensitivity of the measurement, and or the rate of
sweep may be increased or decreased. It should be understood that
such modifications may be made in real-time, dynamically responding
to previous measurements. With every sweep, the monitoring strategy
may use measured information to alter one or more subsequent
sweeps. Furthermore, recursive sweeps may be performed throughout a
testing cycle to verify results of previous sweeps.
[0042] FIG. 6 schematically shows a urine detection system 70,
which includes a urine detection wand 72 including an inducer 74
with an associated exciter coil 75. The wand further includes an
analyzing module 76, and a pair of energy-converting modules that
respectively include sampling coil 78 and reference coil 80. As
shown, the sampling coil and the reference coil are fixed on
opposite sides of the inducer's exciter coil at substantially equal
distances from the exciter coil. One or more signal samples may be
taken at each coil, and used to construct respective magnetic
energy distribution functions. Furthermore, a difference between
the signals measured at each coil may be calculated, and may be
used to calculate a difference function. For example, an array of
sampled differences may be used to plot a curve, which may be
matched to a known curve associated with known conditions. However,
in some embodiments, a difference of a predetermined magnitude
between the respective signals is sufficient to identify a wetness
condition. Urine detection system 70 may, but is not required to,
include one or more energy-converting modules separated from the
urine detection wand. Such energy-converting modules may be used by
urine detection system 70, as described above with reference to
urine detection system 30. The effective detecting range of a urine
detection system employing one or more sampling coils may be
approximately 10 mm, although it is within the scope of the
invention to configure systems with greater or lesser effective
ranges. A range of about 10 mm provides the ability to detect urine
through clothing. With the collaboration of a separated
energy-converting module, the same wand may be used to detect urine
from even greater distances and trough thicker layers such as
blankets.
[0043] In application, detection wand 72 may be used to inspect a
potentially wetted area, such as diaper 82. The sampling coil may
be positioned near the potentially wetted area with the reference
coil thereby being distally positioned. The inducer may produce a
continuous sine wave, a rectangular waveform in either single pulse
or pulse train, or similar signal. Such signals may induce
corresponding signals at the sensing and reference coils, and the
signal at the sampling coil may be compared to the signal at the
reference coil. Urine's effect on the signal at either coil is
typically at least partially dependant on that coil's distance from
the urine, therefore the relative measurement may be useful for
determining if the potentially wetted area is in fact wetted. In a
dry condition, neither coil should be affected by urine, and the
signal at both coils should be similar to one another. However, if
urine is present, it will affect the coils differently, because it
is closer to the sampling coil than the reference coil. The
analyzing module may identify such a difference as being caused by
a wet condition. Furthermore, the analyzing module may examine the
character of each array of signal samples, such as by comparing the
characteristics of an array of samples to characteristics of
pre-measured signal arrays associated with known conditions, to
detect the presence and/or quantity of urine. The above-described
configuration permits the system to use relatively high gain
settings to distinguish relatively small changes in the common
magnetic field by overcoming common environmental factors including
noise, temperature changes, etc. Furthermore, the configuration
allows the wand to test virtually any potentially wetted area, and
is not restricted to areas at which an energy-converting module has
been placed.
[0044] While embodiments of the present invention have been
particularly shown and described, those skilled in the art will
understand that many variations may be made therein without
departing from the spirit and scope as defined in the following
claims. The description should be understood to include all novel
and non-obvious combinations of elements described herein, and
claims may be presented in this or a later application to any novel
and non-obvious combination of these elements. Where the claims
recite "a" or "a first" element or the equivalent thereof, such
claims should be understood to include incorporation of one or more
such elements, neither requiring nor excluding two or more such
elements.
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